I think the real problem with this, is that it contradicts 3 of its own elements creatures
Lava golem, Ruby Dragon (up) and Seraph, Seraph more so.
two of them Ser. And Golem have only have 1 hp, lava golem shouldn't be too much of a problem as it can grow with
,
However if you have Seraph out already and either its on its first turn or you don't have any
,
Then it becomes a problem and you can't use the ability unless you want to kill your own valuable creature.
Use this twice and your Ruby Dragon is dead.
If you want to make this work with those creatures, you must have duo to buff your creatures against it.
Even if they did survive,
Your own creatures become more susceptible to mass cc or Devour.
Otherwise this is more so for duo and helps other elements much more than its own.
As mass cc, it is almost questionable in terms of efficiency, you will kill one strong creature with weak hp,
But on the other hand you will buff a weaker creature with more hp.
This mechanic is also a simple repetition of Rage pot but weaker and AoE instead.
the idea is not bad though it needs to be reworked a bit.